How the World Record Affected Age-Graded Percentages

Dennis Kimetto's new world record in Berlin has altered the reality of male marathoners.

Their age-graded percentages have shifted.

What the heck is an age-graded percentage? Good question.

Okay. Let's say a 30-year-old man runs a 3:00 marathon, and a 60-year-old man runs a 3:30. The younger runner did better, right? Wrong. Not when you factor in "age-graded scoring." That's a system in which runners are scored against each other, but on a level playing field. How do you level the field? Another good question.

Well first, you pit the 30 year old against the "ideal" finish time for a guy his age, which is the current world record. You do that by going to an online age-graded calculator, and plugging in his gender, age, distance, and finish time, then hitting 'calculate,' or you could just do basic math. The calculator spits out his performance percentage, which is 68.55%. Because he's in the 23 to 35 age group, this number is simply the calculation of his time divided into the world record. (This doesn't mean that he's faster than 68% of men his age, contrary to the popular misconception.)

Now, plug in the older guy's digits. The calculator gives him a score of 72.05%. Where this number came from is a little more complicated. For men over the age of 35 (or under the age of 23), the runner's time is multiplied by a factor – for 60-year-olds, it's 0.8155 – that adjusts it down to a time that would be an equivalent effort for a 30-year-old. The full list of factors for both men and women is calculated and shared by World Masters Athletics.

So, about that level playing field: When each of our two runners is compared against the standard for his age and gender, the older runner's performance is superior.

The whole reason this complicated system exists is so that super-nerdy, hyper-competitive runners can judge themselves against others regardless of age or sex. It also exists to make you feel better about getting old. Remember: While your times will go down, if you keep on keepin' on, your age-group score could actually go up. Which is exciting.

Back to Kimetto, the reason we're talking about this in the first place. When he ran 2:02:57, he really wrecked things for some people, specifically, men. When Kimetto lowered the world record by a whopping 26 seconds, the age-graded percentages for all male marathoners changed, too. And not for the better. So this week, our 30-year-old, three-hour, male marathoner has an age-graded score of 68.31% (compared to 68.55% a week ago), and our 60-year-old dude has a 71.79% (a week ago, his was 72.05%). Which means both runners are slightly less awesome than they were just a few days ago.

(And in case you were wondering, since no woman has come close to breaking Paula Radcliffe's world record time of 2:15:25, which she set in 2003, age-graded percentages for women haven't budged.)

Here's the Kimetto effect on a range of men's ages and finish times:

Age

3 Hours

4 Hours

5 Hours

UsingOld Record2:03:23

UsingNew Record2:02:57

UsingOld Record2:03:23

UsingNew Record2:02:57

UsingOld Record2:03:23

UsingNew Record2:02:57

20

69.41%

69.17%

52.06%

51.88%

41.65%

41.50%

30

68.55%

68.31%

51.41%

51.23%

41.13%

40.98%

40

70.24%

69.99%

52.68%

52.49%

42.14%

42.00%

50

76.53%

76.26%

57.40%

57.19%

45.92%

45.76%

60

84.05%

83.76%

63.04%

62.82%

50.43%

50.26%

70

93.22%

92.89%

69.92%

69.67%

55.93%

55.74%

***

Note: The Runner's World Age Graded Calculator (like most others on the web) was built using Paul Tergat's 2003 world record of 2:04:55. Since that's a slower time than the current world record, or even the previous world record, runners get a slightly better score with our calculator. So the same 3:00:00 marathon run by a 30-year-old man would return a 69.4% in the RW tool, and the 3:30:00 by the 60-year-old man would return a 72.94%. Head spinning yet?

Update: We published an addendum to this article to help explain the logic used.

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